Two Years Study of Frequency and Antimicrobial Resistance Patterns of Escherichia coli Strains Isolated from Clinical Specimens in Northern Iran

According to the reports from World Health Organization, increased use of antibiotics and bacterial resistance has become a worldwide issue. Resistance to antimicrobial agents in Escherichia coli clinical strains is increasing. The objective of this study was to determine the antibiotic resistance patterns and frequency of multidrug resistance (MDR) phenotype in Escherichia coli isolated from patients in two major hospitals of Sari, north Iran. In this descriptive-analytical study, a total of 13322 clinical specimens were collected from patients. All the specimens were evaluated to determine the presence of E. coli strains using conventional biochemical tests and API kit. Susceptibility testing against twelve antibiotics was determined using the disk-diffusion method. Results were interpreted in accordance to the Clinical and Laboratory Standard Institute (CLSI) protocol. Out of 13322 studied samples, 964 (7.23%) E. coli strains were identified. In two hospitals, high resistance to ampicillin and cefalexin was presented in 621 (64.4 %) and 402 (41.7 %) isolates, respectively. The highest antibiotic resistance was observed in the burn unit, the burn intensive care unit (ICU) and the burn restoration section, while all the strains (eight) that were isolated from the neonatal-ICU, were sensitive to all the tested antibiotics except cefalexin, nitrofurantoin, nalidixic acid, and ampicillin. Also, strains isolated from urine, wound, stool, and blood samples were resistant to all tested antibiotics. Increased resistance to different antibiotics in burn hospitals has created increasing concern. Very high resistance to some antibiotics indicates that these drugs are misused in therapeutic centers and highlights that infection control measures should be arranged in the ICUs of our hospitals.